Student, 19, plotted school massacre after brutally murdering his mother, sister and brother in bloody shotgun rampage at home

A teenager who has pleaded guilty to murdering his mother and two siblings at their family home planned to carry out a school shooting, police have revealed.

Nicholas Prosper had been due to go on trial next week accused of killing his mother Juliana, 48, sister Giselle, 13, and brother Kyle, 16, in a shotgun rampage on September 13 last year.